<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>demo</title>
</head>
<body>
    <form action="Demo.php" method="post" enctype="multipart/form-data">
        <div class="form-group">
            <input type="file" name="file">
        </div>
        <button type="submit" class="btn btn-primary">提交</button>
    </form>
</body>
</html>